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[ThinLTO] Use original alias visibility when importing 

Summary:
When we import an alias, we do so by making a clone of the aliasee. Just
as this clone uses the original alias name and linkage, it should also
use the same visibility (not the aliasee's visibility). Otherwise,
linker behavior is affected (e.g. if the aliasee was hidden, but the
alias is not, the resulting imported clone should not be hidden,
otherwise the linker will make the final symbol hidden which is
incorrect).

Reviewers: wmi

Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62535

llvm-svn: 361989
This commit is contained in:
Teresa Johnson 2019-05-29 16:50:46 +00:00
parent 98a797c224
commit 5b2088d1fa
3 changed files with 8 additions and 7 deletions
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5
llvm/lib/Transforms/IPO/FunctionImport.cpp
View File

@ -1053,9 +1053,10 @@ static Function *replaceAliasWithAliasee(Module *SrcModule, GlobalAlias *GA) {
ValueToValueMapTy VMap;
Function *NewFn = CloneFunction(Fn, VMap);
// Clone should use the original alias's linkage and name, and we ensure
// all uses of alias instead use the new clone (casted if necessary).
// Clone should use the original alias's linkage, visibility and name, and we
// ensure all uses of alias instead use the new clone (casted if necessary).
NewFn->setLinkage(GA->getLinkage());
NewFn->setVisibility(GA->getVisibility());
GA->replaceAllUsesWith(ConstantExpr::getBitCast(NewFn, GA->getType()));
NewFn->takeName(GA);
return NewFn;

2
llvm/test/ThinLTO/X86/Inputs/alias_import.ll
View File

@ -5,7 +5,7 @@ target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
@globalfuncLinkonceAlias = linkonce alias void (...), bitcast (void ()* @globalfunc to void (...)*)
@globalfuncWeakODRAlias = weak_odr alias void (...), bitcast (void ()* @globalfunc to void (...)*)
@globalfuncLinkonceODRAlias = linkonce_odr alias void (...), bitcast (void ()* @globalfunc to void (...)*)
define void @globalfunc() {
define hidden void @globalfunc() {
entry:
ret void
}

8
llvm/test/ThinLTO/X86/alias_import.ll
View File

@ -38,7 +38,7 @@
; PROMOTE-DAG: @linkonceODRfuncLinkonceAlias = weak alias void (...), bitcast (void ()* @linkonceODRfunc to void (...)*)
; PROMOTE-DAG: @linkonceODRfuncLinkonceODRAlias = weak_odr alias void (...), bitcast (void ()* @linkonceODRfunc to void (...)*)
; PROMOTE-DAG: define void @globalfunc()
; PROMOTE-DAG: define hidden void @globalfunc()
; PROMOTE-DAG: define internal void @internalfunc()
; PROMOTE-DAG: define weak_odr void @linkonceODRfunc()
; PROMOTE-DAG: define weak_odr void @weakODRfunc()
@ -52,11 +52,11 @@
; IMPORT-DAG: define available_externally void @linkonceODRfuncAlias
; IMPORT-DAG: define available_externally void @linkonceODRfuncWeakODRAlias
; IMPORT-DAG: define available_externally void @linkonceODRfuncLinkonceODRAlias
; IMPORT-DAG: define available_externally void @globalfuncAlias()
; IMPORT-DAG: define available_externally dso_local void @globalfuncAlias()
; IMPORT-DAG: declare void @globalfuncWeakAlias()
; IMPORT-DAG: declare void @globalfuncLinkonceAlias()
; IMPORT-DAG: define available_externally void @globalfuncWeakODRAlias()
; IMPORT-DAG: define available_externally void @globalfuncLinkonceODRAlias()
; IMPORT-DAG: define available_externally dso_local void @globalfuncWeakODRAlias()
; IMPORT-DAG: define available_externally dso_local void @globalfuncLinkonceODRAlias()
; IMPORT-DAG: define available_externally dso_local void @internalfuncAlias()
; IMPORT-DAG: declare void @internalfuncWeakAlias()
; IMPORT-DAG: declare void @internalfuncLinkonceAlias()